It's a bit theatrical, but the closest thing feels like cupping a hand to the side of your mouth like you're saying something sotto voce. It only really works if you have a reason to downplay what you're saying rather than just any random aside though.
For body language more generally, you could just take a half step to the side with a bit of a head tilt or wave of the hand (feels more natural for something like a monologue though).

That op-ed is from a different author, in a different newspaper, over a decade ago. Not sure what it proves other than "different Israelis have held contrasting political opinions at various points in time."